A transport and aggregation network includes network elements which offer transport and aggregation of services, such as SONET/SDH, Optical Transport Network (OTN), Ethernet, Storage Area Network (SAN), Video, and the like. Service providers and enterprises deploy such networks to provide connectivity. Typically, when TDM and packet (e.g., Ethernet) connections are co-resident on a given card or system, they physically use separate infrastructure on the card or system, such as a unique TDM fabric and a unique packet fabric each with physically separate interfaces. This is the case for a transport and aggregation network element with either a central fabric or meshed configuration. Additionally, systems originally designed for only one traffic type may not have planned for separate interfaces. For example, a transport and aggregation platform may have been deployed with wavelength division multiplexing (WDM) solely to transport and aggregate SONET/SDH traffic, and to add packet connections, a new system or switch fabric must be installed along with the existing platform. With separate infrastructure, comes an increase in cost (e.g., distinct TDM and packet switches). Note, this also assumes that the platform (new or legacy) has been designed with forethought to accommodate both sets of infrastructure.
In systems that do not accommodate distinct separate physical interfaces for TDM and packet, mixing native packet traffic (Open Systems Interconnect (OSI) layer two) and native TDM (OSI layer one) traffic over a common physical interface is difficult, since formats and requirements differ between the types of traffic. This is complicated further when both traffic types need access to a shared resource such as a packet processor which may not be able to dedicate separate interfaces to the traffic flows.
Existing TDM systems offer packet connections with TDM through protocols such as Packet-over-SONET (POS), Virtual Concatenation (VCAT), Generic Framing Procedure (GFP), High-Level Data Link Control (HDLC), Point-to-Point Protocol (PPP), and the like. However, these protocols either provide dedicated point-to-point connections or offer limited layer two switching capabilities.
Ethernet increasingly is being considered as a replacement to SONET/SDH for metropolitan and wide-area transport and aggregation networks. Where SONET/SDH traditionally was designed for efficient multiplexing and transport of TDM-oriented traffic, Ethernet is considered as the transport solution for packets. Thus systems and methods for combining TDM and packet connections in a single system simultaneously in a meshed switching architecture are needed.